> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ionworks.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Initiate a signed URL upload for measurement data

> Initiate upload for time_series or file measurement data.



## OpenAPI

````yaml https://api.ionworks.com/openapi.json post /cell_instances/{cell_instance_id}/cell_measurements/initiate-upload
openapi: 3.1.0
info:
  title: FastAPI
  version: 0.1.0
servers:
  - url: https://api.ionworks.com
    description: Production
security: []
paths:
  /cell_instances/{cell_instance_id}/cell_measurements/initiate-upload:
    post:
      tags:
        - Cell Instances
        - Cell Measurements
      summary: Initiate a signed URL upload for measurement data
      description: Initiate upload for time_series or file measurement data.
      operationId: >-
        initiate_measurement_upload_cell_instances__cell_instance_id__cell_measurements_initiate_upload_post
      parameters:
        - name: cell_instance_id
          in: path
          required: true
          schema:
            type: string
            title: Cell Instance Id
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/InitiateUploadRequest'
      responses:
        '201':
          description: Successful Response
          content:
            application/json:
              schema: {}
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HTTPValidationError'
components:
  schemas:
    InitiateUploadRequest:
      properties:
        measurement:
          additionalProperties: true
          type: object
          title: Measurement
          description: Measurement data with custom fields
        measurement_type:
          $ref: '#/components/schemas/MeasurementType'
          description: Type of measurement. Use 'file' for file uploads.
          default: time_series
        filenames:
          anyOf:
            - items:
                type: string
              type: array
            - type: 'null'
          title: Filenames
          description: List of filenames to upload (required for file type).
      type: object
      required:
        - measurement
      title: InitiateUploadRequest
      description: Request model for initiating a signed URL upload for measurement data.
    HTTPValidationError:
      properties:
        detail:
          items:
            $ref: '#/components/schemas/ValidationError'
          type: array
          title: Detail
      type: object
      title: HTTPValidationError
    MeasurementType:
      type: string
      enum:
        - time_series
        - file
        - properties
      title: MeasurementType
      description: |-
        Shape of the data stored in a cell measurement.

        - ``time_series`` — cycling / diagnostic data uploaded as columnar
          time series (and optional step summaries). Default for new
          measurements.
        - ``file`` — an opaque file upload (raw cycler export, image, other
          binary). Metadata about the file is captured in
          ``file_metadata``; the file content lives in object storage.
        - ``properties`` — a flat key/value set of measured properties
          (thickness, mass, DCIR, initial capacity, …) with no time-series
          data. Numeric values use the Quantity format.
    ValidationError:
      properties:
        loc:
          items:
            anyOf:
              - type: string
              - type: integer
          type: array
          title: Location
        msg:
          type: string
          title: Message
        type:
          type: string
          title: Error Type
        input:
          title: Input
        ctx:
          type: object
          title: Context
      type: object
      required:
        - loc
        - msg
        - type
      title: ValidationError

````